1. Field of the Invention
The present invention relates to pipe fittings and joints for food processing and other applications where sanitary and aseptic conditions are required. Processing of foods and other products such as pharmaceuticals, requires appropriate handling and precautions to prevent contamination of the product and to provide sanitary equipment. One area in food processing equipment which is particularly susceptible to the entry of contaminants is pipe joints where fittings are used to couple tube or pipe sections.
2. Description of Related Art
In the past, pipe and tube fittings for sanitary and aseptic processing have utilized pipe joints sealed by convential O-rings or gaskets in which two or more O-ring or gasket seals or a combination of them are typically provided to form a barrier between products passing through the piping and the exterior of the fitting joint. To further guard against contaminants, steam seals have been provided at the joints basically consisting of a surrounding annular steam filled chamber around the joint. Necessary inlet and outlet steam piping is also required. A major disadvantage of the use of steam seals in some applications is that certain products are susceptible to the effects of heat which may adversely affect certain food products and their end quality. Furthermore, steam is costly in that it requires a source of steam, piping of steam to and from the individual joints and their efficiency is often affected by the build-up of scale deposits from the steam itself in the joints. In addition, conventional O-rings in aseptic processing require high quality surface finishes at the seal joint. Lastly, even the best O-rings are still susceptible to some passage of contaminants such as bacteria, as well as the trapping and build-up of product at the O-ring.